The present invention relates to a compressor and more particularly to a swash plate in a swash plate type variable displacement compressor for an air conditioner of a vehicle.
A swash plate type variable displacement compressor generally has a swash plate, which is operatively connected to a drive shaft. The swash plate is integrally rotatable with a drive shaft and tiltable with respect to the axis of the drive shaft. A single-headed piston engages with the swash plate through a pair of shoes. The rotation of the drive shaft is converted to the reciprocation of the piston through the swash plate and the shoes. The displacement of the compressor is adjusted by varying the inclination angle of the swash plate with respect to the axis of the drive shaft.
The swash plate is generally made of iron series. If the weight of the swash plate is relatively light, the moment of inertia due to the rotation, which influences the adjustment of the inclination angle of the swash plate, does not appropriately work. Accordingly, especially when the drive shaft rotates at high speed, or when the compressor operates at high speed, controllability of the displacement of the compressor may deteriorate. Therefore, since copper series is heavier in the same shape than iron series, the swash plate made of copper series is also applied.
Since the shoes slide on the swash plate, sliding surfaces between the shoes and the swash plate may abrade. Both ensuring controllable displacement of the compressor and relatively high sliding performance of the swash plate with respect to the shoes upon operating at high speed are achieved by utilizing copper series material containing lead as solid lubricant for forming base member of the swash plate. However, utilizing much lead, which is a toxic substance, is undesirable.
The present invention addresses the above-mentioned problems traceable to a material containing relatively much lead by adopting another structure without containing relatively much lead.
According to the present invention, a swash plate type variable displacement compressor has a housing, a drive shaft, a swash plate and a piston. The housing is formed by a cylinder block, a front housing, and a rear housing. The drive shaft is rotatably supported by the housing. The swash plate is connected to the drive shaft, and is integrally rotatable with the drive shaft and tiltable relative to the drive shaft. The piston engages with the swash plate through a pair of shoes. Rotation of the drive shaft is converted to reciprocation of the piston through the swash plate and the shoe, and the displacement of the compressor is adjusted by varying the inclination angle of the swash plate with respect to the axis of the drive shaft. The swash plate includes a base member made of copper series and a sliding layer coating a sliding surface of the base metal relative to the shoe.